We had this issue - couldn't hear the sat nav though the radio volume was fine. Then noticed a blue shape in the top right hand corner of the navigation screen. Clicking on this gives a screen with a volume slider control at the bottom, which controls sat nav volume.
Hope this helps!

Hi Cozy Buz,
We have just acquired a Pioneer AVH X5800DAB model with our new Burstner MH. Was so glad when we got it because of the DAB, but now not so sure. It has a fantastic number of menus but I can't even get it to search for a location by postcode, no camp site locations and the only choice of dimensions is to choose "Lorry" from the menu. I found location by co-ordinates once, but not since.
So I think I will continue to carry our Garmin Camper GPS which has its moments, but is dedicated to giving you a route -not radio, CD/DVD, USB, Bluetooth, reversing camera as well! Who wants to be struggling with multiple menus when you're driving a "Lorry"?
I will say though that I did find the blue lozenge shape discussed earlier in the top RH corner of the screen - in satnav view.

We found that to search by postcode you have to enter the postcode into the Town field when you Create Route or use the Find function.

Our dealer had set up a new vehicle profile for the motorhome - though we managed to delete it by accident! We set up a new one by modifying the lorry profile with our dimensions - hope that was the right profile to edit! - we could perhaps have edited the car profile instead... I guess it depends upon what restrictions are applied to each profile type.

Haven't looked for campsite locations - if they're in there I would think they'd be as Points of Interest - but I suspect they may not be included.

Glad you found the blue lozenge! I was struggling to decide how to describe it - a blue square or circle would've been so much easier!